Pulpal diagnosis of teeth presenting with condensing osteitis prior to endodontic treatment — a retrospective study

Drs. Brian Shaughnessy, Margaret Jones, Ricardo Caicedo, Joseph Morelli, Stephen Clark, and Ms. Jennifer Osborne review the occurrence of teeth presenting with condensing osteitis and their associated pulpal diagnosis over a 2-year period.

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Introduction
The most recent publication of diagnostic terminology accepted by the American Association of Endodontists (AAE) and American Board of Endodontics (ABE) includes condensing osteitis as a periapical diagnosis.

It is defined as a “diffuse radiopaque lesion representing a localized bony reaction to a low-grade inflammatory stimulus, usually seen at apex of tooth.” While it is included on this list of periapical diagnoses, it may not always be used when indicated as the periapical diagnosis. Rather, it may sometimes be used as a radiographic finding that is noted secondary to another clinical periapical diagnosis.

Condensing osteitis usually presents as a radiopaque area adjacent to and associated with the apex of a tooth that has either a widened PDL or a periapical radiolucency8 (Figure 1). The outer edge of the radiopacity does not have a radiolucent zone, as would be found with focal cementosseous dysplasia. Furthermore, there is no associated expansion of the jaw that would be noted clinically in association with the radiographic finding.
Few studies have investigated the prevalence of this radiopaque radiographic finding, with most finding it less than 7% of the time.7 The most extensive published evaluation, which reviewed 1,149 roots receiving endodontic treatment within a 12-month period, found that 2% of roots showed preoperative condensing osteitis.2 Comparatively, the authors found 28% of the roots to have a periapical radiolucency. Condensing osteitis appears to be most often associated with mandibular posterior teeth,1-3 and many have noted it to be found more often in adolescents than in adults.8-9 There is also some evidence that the prevalence may be different for different ethnicities.4

Recently, Green and Walton performed a histologic evaluation of condensing osteitis.5 They identified 16 teeth with a radiographic diagnosis of condensing osteitis in cadaver mandibles and performed block resections in order to examine the teeth and periapex histologically. The results revealed replacement of marrow spaces and cancellous bone by dense, compact bone. Additionally, they noted areas of fibrosis replacing fatty marrow in some of the samples. Interestingly, in 14 of the 16 samples, minimal or no inflammation was found. This led them to speculate that “condensing osteitis is not always an inflammatory lesion but is a bony proliferative response to pulpal inflammation.” The authors, however, did stress that while they did not identify direct inflammation in the bone causing the reaction, “there must be sufficient osteogenic stimulation from inflammatory mediators from the pulp or apical foramen region” to initiate these bony changes.

Green and Walton also noted that there was an “association of condensing osteitis with pulpal damage, inflammation, and/or necrosis.” This observation has previously been made by others8 and is consistent with the theory of pulpal inflammation and associated inflammatory mediators initiating the bony changes. Moreover, it has been shown that following root canal treatment of teeth presenting with condensing osteitis, many show complete radiographic reversion to a normal periapex.1,2

It has also been observed that a pulpal diagnosis of either pulpitis or pulp necrosis can be associated with condensing osteitis. The purpose of this study was to review the occurrence of teeth presenting with condensing osteitis and their associated pulpal diagnosis over a 2-year period in a postgraduate endodontic program.
 
Materials and methods
A retrospective records review was performed on patients receiving non-surgical endodontic treatment in the University of Louisville postgraduate endodontic clinic between July 1, 2011, and June 30, 2013. All patients receiving non-surgical root canal therapy during this 2-year period were included.

Electronic patient records as well as digital radiographic images were reviewed by two reviewers independently and in duplicate. All patient records had been recorded using axiUm software, and all radiographs were taken using Kodak 6200 sensors and reviewed using MiPACS® (Medicor Imaging) software. Data recorded included patient age and gender, treated tooth number, pulpal and periapical diagnosis, and radiographic presence of a periapical radiolucency, or condensing osteitis.

Presence of condensing osteitis was determined jointly with both reviewers achieving agreement. Descriptive statistics, chi-square analysis, and ANOVA with Tukey’s post hoc test in SPSS version 22 were used for analysis. Significance was determined using α less than 0.05.

Results
Data was collected from 1967 teeth receiving non-surgical root canal therapy in 1,670 patients. Thirty-five teeth in 35 patients were identified with a radiographic appearance consistent with condensing osteitis. This constituted 1.8% of the treated teeth.

The average age of patients in the total patient population treated was 36.7 ± 18.4 years, while the average age of patients presenting with condensing osteitis was 26.3 ± 15.7 years. Table 1 shows the frequencies of patient age groups in cases with condensing osteitis. There was a statistically significant association between age and prevalence of preoperative condensing osteitis with it being more frequent in younger patients (p < 0.01). Condensing osteitis was found more often in female patients (Table 2). However, this was not found to be statistically significant (p = 0.12).

As seen in Table 3, condensing osteitis was found most frequently with mandibular first molars. This tooth type accounted for 88.6% of the cases observed (31/35). Condensing osteitis was associated with 6.9% of all mandibular first molars treated in this study population.

The most common pulpal diagnosis among cases presenting with condensing osteitis was symptomatic irreversible pulpitis (SIP). This pulpal diagnosis occurred in 22 of the 35 cases (63%). Pulp necrosis was found in 11 of the 35 cases (31%). One case had a pulpal diagnosis of asymptomatic irreversible pulpitis, and one case had a diagnosis of previously initiated (Figure 2).

Discussion
In this study, all radiographs were reviewed by two postgraduate endodontic residents, and agreement was verified by a board-certified endodontist with 38 years of clinical experience. In order to be classified as condensing osteitis, clear evidence of a focal area that was more radiopaque than the surrounding bone proximal to the root apex had to be noted. Radiopacities that were considered to be a superimposition of a radiopaque structure such as the mylohyoid ridge or mandibular torus were not counted as condensing osteitis. It is possible that some cases of condensing osteitis could have been obscured by overlapping radiopaque structures. This leads the authors to believe that our overall prevalence of 1.8%, though consistent with previous findings,2 may be a slight underestimation.

Additionally, previous investigations have found mandibular second molars to account for approximately 20% of the cases of condensing osteitis2; however, this study did not find any cases associated with mandibular second molars. This could also be due to the superimposition of radiopaque structures that represented normal anatomy obscuring the ability to clearly identify if there was a change in bony density due to condensing osteitis. This could have resulted in lowering the number of cases found with mandibular second molars.

Bony changes due to condensing osteitis could be just as likely to occur in other areas of the jaws but are more easily seen with periapical images in the area of the mandibular premolars and first molar, making those the most likely areas to be diagnosed with condensing osteitis. A similar-appearing radiopaque lesion, idiopathic osteosclerosis, has also been found to occur more often in the posterior mandible.6 This could also be attributed to the same ease of diagnosis in this area, or an indication that the posterior mandible is a more favorable site for such dense bony changes. A CBCT study could lend important insight in determining if the osseous changes are more likely to be found in this area or simply more easily detected by periapical radiographs in the posterior mandible.

The findings of this study support the theory that either an inflamed or a necrotic pulp are associated with condensing osteitis. It remains unclear if the osseous changes can occur from a necrotic pulp alone, or if the changes occur during the pulpitis stage and are simply noted after the pulp has become necrotic. This study found condensing osteitis associated more often with symptomatic irreversible pulpitis than with pulp necrosis.
The mechanism by which these osseous changes occur remains to be investigated. The current theory has been that the osseous changes are associated with chronic low-grade inflammation. Further investigation into the mediators and process responsible for the formation and maintenance of condensing osteitis, as well as genetic factors that might play a role in the occurrence of these bony changes, rather than the formation of a periapical radiolucent lesion would be beneficial to understanding this entity.

Conclusions
In this retrospective review of 1,967 teeth treated over a 2-year period in the graduate endodontics clinic at the University of Louisville, condensing osteitis was diagnosed in 1.8% of the cases. It was most common in mandibular first molars and in patients under the age of 20. Teeth presenting with condensing osteitis had a pretreatment pulpal diagnosis of symptomatic irreversible pulpitis in 62.9% of the cases.

Bibliography
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